Normally, when people travel around or go outside in winter, they usually carry thermally insulated cups for carrying drinking water. Currently, most of thermally insulated cups are made of plastic materials or stainless steel alloy.
Plastic materials are cheap and light in weight. However, when such materials encounter with hot water, some unhealthy substances can be easily generated which causes the safety property of thermally insulated cups made of plastic materials not good. Further, the thermal expansion and cold contraction degree of plastics is relative higher which will cause the sealing property of thermally insulated cups made of plastic material decreased after long-term use.
Shortcoming of thermally insulated cups made of stainless steel alloy is that, when carbonated drinks, alkali drinks or tea is put in this type of cups, acids or alkalis in such drinks may corrode stainless steel alloy and metal ions can be generated easily. After long-term use, thermally insulated cups made of stainless steel alloy can easily generate a taste of rust, which will produce negative effects to users.